Who is Iva from Eat, Pray, Love: One Woman's Search for Everything Across Italy, India, and Indonesia and what is their importance?

Iva is Elizabeth Gilbert's Lebanese-American friend, Iva grows up in war-torn Beirut and becomes the calmest person in the world. While they are driving across Kansas, Iva suggests that Liz write a petition to God stating her specific desire to be free of her destructive marriage.